Updated to make the NPC more real when building and not teleport at any time (tell me on discord if not)
I can't make the NPC build lower, if you want him to go lower, you can do /npc speed [from 0.1 to 1] and also /constructor timeout [0.1 to 1.0]
Added support for rightclick on NPC (missed it before when added support for leftclick) with the same permission constructor.npc.click
Have fun !